Defensive tackles have become as essential in the NFL draft as bread and milk on a grocery shelf during a winter storm watch.

In the last three drafts, 16 defensive tackles — more than any other position — have been picked in the first round. Last year, five defensive tackles were among the first 13 selections.

They are coveted because of the impact they can have. A good defensive tackle can suppress an opponent's inside running game. He can collapse the pocket and torment the quarterback. He can draw double-teams, making it easier for linebackers to make tackles or ends to rush the passer. His production can be measured in the disruption and havoc he causes as much as in the sacks and tackles he makes.

"It's a position that, when played right, can really take a game over," says Bucs assistant head coach/defensive line coach Rod Marinelli.

Albert Haynesworth, a No. 1 pick from Tennessee, became a force in his second year with the Titans.
Craig Jones /Getty Images

Trouble is, it's a position that is difficult to project. Rarely does a defensive tackle take games over in his first or second season. Warren Sapp struggled as a rookie in 1995, and it wasn't until about midway through the 1996 season that he picked up on first-year coach Tony Dungy's defense. Marcus Stroud (Jaguars, 2001), Casey Hampton (Steelers, 2001) and Albert Haynesworth (Titans, 2002) are more recent examples of defensive tackles who needed time to develop into forces.

The Rams have drafted three defensive tackles in the first round in recent years — Damione Lewis and Ryan Pickett in 2001 and Jimmy Kennedy last year — and none has lived up to expectations. The Browns' Gerard Warren, the third overall pick in the 2001 draft, also hasn't measured up.

Of the six defensive tackles drafted in the first round last year, only Kevin Williams of the Vikings (10 1/2 sacks, one interception, three passes defensed) was highly productive. And he played end for most of the season.

There are several reasons it takes defensive tackles time to adjust to the NFL.

In college, they often can be dominant purely because of their size and athleticism. In the NFL, they face offensive linemen who have similar physical talent.

They play with poor technique. They often don't know how to use their hands and don't understand blocking schemes. They tend to play too upright and glance into the backfield — "I call it turkey necking," says Marinelli — which allows offensive linemen to get under their pads and gain leverage.

They don't play at a consistent level. Their motors rev up momentarily, then idle for a long time.

"When we look at guys in the draft at that position," says Ravens college scouting director Eric DeCosta, "typically we see what we refer to as 'flash players.' They show a tremendous ability on some plays and then sort of disappear on other plays."

But a defensive tackle with the potential to be great can be worth the risk of a high draft pick and the time it takes for him to develop. Take Stroud. The 13th pick in the 2001 draft, Stroud admits he struggled as a rookie.

"I had a hard time adapting a little bit," he says. "I wasn't using my hands as well as I was supposed to." That made it difficult to shed blocks. "My second year, I started coming into my own, and I think I've been getting better ever since."

This season, under first-year head coach Jack Del Rio, Jacksonville switched from a two-gap defense to a one-gap scheme. "It gave me a chance to be more active, a little bit more reckless and use my physical attributes to my advantage," says Stroud, who had 82 solo tackles — including 12 for losses, 4 1/2 sacks, 37 quarterback pressures and five passes defensed. He was selected as a Pro Bowl starter.

"This year was a big step for him," says Titans director of player personnel Rich Snead. "He was more of a force as a rusher and did a lot better penetrating. He was more level. There weren't as many valleys in his play."

Stroud and second-year defensive tackle John Henderson combined for 11 solo tackles when the Jaguars played the Ravens November 2. DeCosta says the Jaguars' defensive line was one of the best at controlling the interior against the Ravens and shutting down running back Jamal Lewis (68 yards in 21 carries, with a long run of 10 yards).

Defensive tackles are expected to be hot commodities again in this year's draft. The War Room lists 11 among its top 80 prospects, and it projects Oklahoma's Tommie Harris, Miami's Vince Wilfork and Maryland's Randy Starks as first-round picks.

Of course, all defensive tackles don't come out of the same mold. For example, some scouts believe Harris (6-3, 288) is more like Sapp or Bryant Young, a penetrating, disrupting, pass-rushing type, whereas Wilfork (6-2, 344) would fit better as a nose tackle in a 3-4.

"The key in drafting one of those guys is to get the guy who fits you best, the guy who is going to conform to your system and play with consistency," says DeCosta. "And that's the risk. That position breeds inconsistency. So if you're going to pick one, you better pick the right one."